Friday 3 December 2010 19.05 EST
First published on Friday 3 December 2010 19.05 EST

"The moment when I am no longer more than a writer, I will cease to write." This statement by Albert Camus is Nadine Gordimer's credo, she tells us in a 2006 essay collected in Telling Times, (Telling Times: Writing and Living 1950-2008, Bloomsbury, £35), the magisterial anthology of her non-fiction written since 1950, which serves as a companion to Life Times, a new collection of her short stories.

Camus's statement helps to explain the vitality of this extraordinary writer and the moral gaze she has cast – arch and rigorous – over literature and politics in the past 60 years. It explains why she took herself off to Israel/Palestine well into her 80s to give a lecture on the need to bear witness. It also surely explains why, at the age of 87, she recently decided to lead South African writers in protest against the moves towards restricting press freedom by the ruling African National Congress, the movement she has long supported.

In early essays Gordimer noted the lack of a Camus-like figure, the philosopher-novelist, in anglophone literature. These new collections demonstrate how assiduously she has set out to establish for herself such a role, from her "beautiful old tin-roofed house with room for my books", with Johannesburg's mine-dumps and tough black townships just beyond. She is intensely conscious of her position as a white South African who saw, early on, the evil being done in her name and thus became a "minority-within-a-minority". She has taken what she believes to be her primary burden and turned it into a lifelong moral quest: to be a writer by being more than a writer. This meant finding a way of being engaged in the struggle against apartheid while remaining true to what she describes as the near-mystical gifts of the writer: the ability to move "deep under the surface of human lives", to be "a witness to the unspoken in my society". "Conscionable self-awareness," she tells us, is a "lifetime lodger".

Thus she defines herself against her only equal in South African letters, JM Coetzee. In a 1984 review of The Life and Times of Michael K, she lauds Coetzee's allegorical fiction but finds his approach "challengingly questionable". By not permitting his characters historical agency, Coetzee denies "the indefatigable and undefeatable persistence" of black South Africans in their fight against apartheid. One might be tempted to interpret this objection as the product of its times, but in a postscript (one of only three in 750 pages), she writes: "JM Coetzee took Australian citizenship in 2006." She wants this to be known: she is rooted in her place and writes from it, in a way that Coetzee is not and does not.

But Gordimer also worries at the paradox presented to her by her political commitment. She writes, for example, of authors who have sacrificed their literary gifts to public life, among them Wole Soyinka, Chinua Achebe and Olive Schreiner, the early South African feminist and author (Story of an African Farm). In 1980, when Gordimer must have felt most strongly the pull of the barricades, she wrote that Schreiner "dissipated her creativity in writing tracts and pamphlets rather than fiction", and thus was unable "to put the best she had – the power of her creative imagination – to the service of her fierce and profound convictions, and her political and human insight."

In these two volumes, Gordimer shows that she has succeeded where she believes Schreiner failed. Telling Times displays her intellectual and creative range, from travel writing to polemic, taut reportage to literary criticism. But it is, at its heart, an archaeology of the author's quest for critical engagement, her obsessive turning over what it means to be white – and black - in a country that has changed unimaginably in her lifetime, of what role the writer could and should play in the revolution and in a new democracy. It is relentless, sometimes exhausting, and often of historical rather than literary interest. But it is rich and rewarding, too – and not without Gordimer's acid wit. Who else could get away with snapping at Muriel Spark that she has "stockings dangling to dry above every page"? Most of all, Telling Times opens the door to Gordimer's fiction by revealing the moral imperatives behind such incomparable novels as Burger's Daughter and The House Gun, and the six decades' worth of short stories collected in Life Times.

Inevitably, there are failed experiments, particularly later on, as Gordimer pushes the form to its limits in an attempt to animate political notions or moral predicaments. But there are older stories, such as "Six Feet of the Country", and newer ones, such as "Town and Country Lovers" and "Something Out There", that exemplify Gabriel García Márquez's dictum, cited by Gordimer: "The best way a writer can serve a revolution is to write as well as he can."

Her writing feels effortlessly limpid, particularly when describing the natural world. But there is an awkwardness to her prose – and particularly her dialogue – in many of the stories of cross-racial encounters that mirrors the awkwardness of such encounters themselves. No one is given an easy ride in Gordimer's fiction, least of all the reader: reading, as writing, is a moral undertaking.

Some of her best work is written from, or about, other parts of Africa. She notes in one essay that "to be white in the streets of Accra is to feel oneself curiously anonymous and almost invisible", liberated from both her moral burden and the judgmental gaze of her compatriots back home. Later in her life, she would praise Ernest Hemingway's "The Snows of Kilimanjaro" as "one of the greatest short stories ever written", although it had "nothing to do with Africa". One could say the same about her own brilliant "Friday's Footprints": it is about love, loss and forbearance, rather than about life on a bend of a central African river. In contrast, many of her South African stories self-consciously set out to breathe life into moments of political crisis: defiance campaigns, pass-burnings, arrests under the Immorality Act.

Telling Times reveals how deeply shaken Gordimer was by the Black Consciousness movement of the 1970s, which sought to marginalise whites from the struggle. She wrestled with the edicts of her black comrades: whites needed to be willing to follow, to listen, to struggle too. Her creative task, thus, was to try to imagine "a new kind of posited community, non-racial but somehow conceived with and led by blacks".

Ever diligent, she set herself to write from the perspective of a liberated, black-run country, most notably in July's People. She did not stint when this perspective led her to places of discomfort. In "A Soldier's Embrace", written in the early 1980s, a liberal white couple find themselves sidelined by the new black elite after liberation, and choose to leave. In "The Rendezvous of Victory", a decade later, liberation transforms a hero of the struggle into a puffed-up drunk.

From 1994, Gordimer no longer needed to imagine being the citizen of a black-led democracy, and she revelled in finally being able to talk of "our country" collectively with her black compatriots. Still, by 1999, she was identifying with the Polish poet Czesław Miłosz: "Ill at ease in the tyranny, ill at ease in the republic / In the one I longed for freedom, in the other for the end of corruption." She has remained as engaged as ever: she continues to be a passionate crusader against censorship, and has turned her pen to Aids, the Middle East, global poverty. But in her later stories there is a darkness that is far removed from the idealism that drove her earlier writing. Particularly after 9/11, the visions in her more allegorical works are nothing short of apocalyptic.

One can only speculate on the personal dimensions of this darkness. In recent years Gordimer has lost her husband and many of her closest friends. In one late story, she imagines her three most valued intellectual collaborators, now all dead, gathered at a Chinese restaurant in heaven: Susan Sontag, Edward Said and Anthony Sampson. Though poignant, the story is one of her least successful, perhaps because it is autobiography masquerading as fiction: one wants to hear about their lives together – their charged correspondence over Israel, for example – rather than read a reverie of their communion after death.

Gordimer's early ventures into memoir are witty and insightful. But her resistance to autobiography has set with age: "I am much too jealous of my privacy." This guardedness is evident in the sometimes maddening way she provides no context to the essays and stories in Telling Times and Life Times. And yet their very titles point to their biographical aspirations, and their biographical value. They map the writer's work through time.

Mark Gevisser's A Legacy of Liberation: Thabo Mbeki and the Future of the South African Dream is published by Palgrave Macmillan.